U.S. patent number 4,374,158 [Application Number 06/205,346] was granted by the patent office on 1983-02-15 for process for producing transparent shaped article having enhanced anti-reflective effect.
This patent grant is currently assigned to Toray Industries, Inc.. Invention is credited to Jiro Mibae, Takashi Taniguchi.
United States Patent |
4,374,158 |
Taniguchi , et al. |
February 15, 1983 |
**Please see images for:
( Certificate of Correction ) ** |
Process for producing transparent shaped article having enhanced
anti-reflective effect
Abstract
A transparent shaped article having an enhanced anti-reflective
effect is produced by treating with an activated gas the surface of
a transparent shaped article having a surface layer containing a
finely divided particulate inorganic substance having an average
particle size of from about 1 to about 300 milli-microns. If
desired, the transparent shaped article treated with the activated
gas is coated with a protective coating material.
Inventors: |
Taniguchi; Takashi (Shiga,
JP), Mibae; Jiro (Otsu, JP) |
Assignee: |
Toray Industries, Inc. (Tokyo,
JP)
|
Family
ID: |
26459034 |
Appl.
No.: |
06/205,346 |
Filed: |
November 10, 1980 |
Foreign Application Priority Data
|
|
|
|
|
Nov 14, 1979 [JP] |
|
|
54-146485 |
Sep 4, 1980 [JP] |
|
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55-121745 |
|
Current U.S.
Class: |
427/536; 427/162;
427/164; 427/165; 427/578 |
Current CPC
Class: |
B05D
3/0453 (20130101); B05D 3/148 (20130101); B29C
59/12 (20130101); B29C 59/14 (20130101); G02B
1/111 (20130101); C03C 17/32 (20130101); C03C
23/00 (20130101); B29D 11/00865 (20130101); B05D
2203/35 (20130101); B29K 2105/16 (20130101); B29K
2995/0026 (20130101) |
Current International
Class: |
B05D
3/04 (20060101); B05D 3/14 (20060101); B29C
59/14 (20060101); B29C 59/00 (20060101); B29C
59/12 (20060101); B29D 11/00 (20060101); C03C
17/28 (20060101); C03C 23/00 (20060101); C03C
17/32 (20060101); G02B 1/10 (20060101); G02B
1/11 (20060101); B05D 003/14 () |
Field of
Search: |
;427/39,40,41,162,164,165 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Newsome; John H.
Attorney, Agent or Firm: Miller; Austin R.
Claims
We claim:
1. A process for producing a transparent shaped article having an
enhanced anti-reflective effect, said article either being an
organic material or having a coating of organic material thereon
which comprises treating with an activated gas the surface of a
transparent shaped article, said surface layer comprising a finely
divided particulate inorganic substance having an average particle
size of from about 1 to about 300 milli-microns dispersed in said
organic material.
2. A process according to claim 1, wherein the finely divided
particulate inorganic substance has an average particle size of
from about 5 to about 200 milli-microns.
3. A process according to claim 1 or 2, wherein the finely divided
particulate inorganic substance comprises at least one substance
selected from the group consisting of oxides and halides of
elements of Groups II, III, IV and V of the Periodic Table.
4. A process according to claim 1 or 2, wherein the finely divided
particulate inorganic substance comprises at least one substance
selected from the group consisting of zinc oxide, silicon oxide,
aluminum oxide, titanium oxide, zirconium oxide, tin oxide,
beryllium chloride and antimony oxide.
5. A process according to claim 1, wherein the transparent shaped
article having the surface layer comprising the finely divided
particulate inorganic substance is prepared by dispersing the
finely divided particulate inorganic substance in a transparent
material for the shaped article prior to or during the step of
shaping the transparent material.
6. A process according to claim 1, wherein the transparent shaped
article having the surface layer comprising the finely divided
particulate inorganic substance is prepared by coating a
transparent shaped article with a transparent organic coating
material having dispersed therein the finely divided particulate
inorganic substance.
7. A process according to claim 6, wherein the transparent organic
coating material having dispersed therein the finely divided
particulate inorganic substance is prepared by mixing the finely
divided inorganic substance together with a transparent organic
vehicle component in a volatile dispersing liquid medium.
8. A process according to claim 7, wherein the transparent organic
vehicle component is at least one substance selected from the group
consisting of epoxy resins, acrylic acid ester and/or methacrylic
acid ester copolymers, polyamides, polyesters, amino resins,
urethane resins, polycarbonates, polyvinyl acetate resins,
polyvinyl alcohol resins, styrene resins, transparent vinyl
chloride resins, silicone resins, cellulose type resins and
diethylene glycol bisallyl carbonate polymers.
9. A process according to claim 7, wherein the transparent organic
vehicle component comprises at least one silicon compound selected
from the group consisting of compounds represented by the following
general formula and hydrolysis products thereof:
wherein R.sup.1 and R.sup.2 stand for an alkyl, aryl, halogenated
alkyl, halogenated aryl or alkenyl group having 1 to 10 carbon
atoms or an organic group including an epoxy, methacryloxy,
acryloxy, mercapto, amino or cyano group, each of R.sup.1 and
R.sup.2 is bonded to the silicon atom by the Si-C linkage, R.sup.3
stands for an alkyl, alkoxyalkyl or acyl group having 1 to 4 carbon
atoms, a and b are numbers of 0, 1 or 2, and the sum of a plus b is
1 or 2.
10. A process according to claim 1 or 2, wherein the amount of the
finely divided particulate inorganic substance contained in the
transparent shaped article is 5 to 80% by weight in the surface
layer portion to be treated with the activated gas.
11. A process according to claim 5, 6 or 7, wherein the finely
divided particulate inorganic substance to be dispersed is in the
form of a colloidal dispersion in a liquid medium.
12. A process according to claim 1, wherein the body of the
transparent shaped article is made of a transparent material
selected from glass, polymethyl methacrylate, methyl methacrylate
copolymers, polycarbonates, diethylene glycol bisallyl carbonate
polymers, polyesters and epoxy resins.
13. A process according to claim 1, wherein the activated gas is a
gas containing an ion, an electron and/or an excited gas, formed
from oxygen, air, nitrogen, argon or freon by using a corona
discharge means or a direct current, low frequency, high frequency
or micro-wave high voltage discharge means.
14. A process according to claim 1, wherein the activated gas is a
cold plasma obtained by means of direct current, low frequency,
high frequency or micro-wave high voltage discharge under a
pressure of 10.sup.-2 to 10 Torr.
15. A process according to claim 1, wherein the transparent shaped
article treated with the activated gas is coated with a protective
coating material.
16. A process according to claim 15, wherein the protective coating
material is at least one thermosetting resin selected from the
group consisting of epoxy resins, acrylic acid ester copolymers,
methacrylic acid ester copolymers, polyester resins, alkyd resins,
unsaturated polyester resins and silicone resins.
17. A process according to claim 15 or 16, wherein the amount of
the protective coating material is in the range of from 5 mg to 1 g
per m.sup.2 of the surface of the transparent shaped article to be
coated.
18. A process for producing a transparent shaped article having an
enhanced anti-reflective effect, said article being either organic
material or having a coating of organic material thereon, which
comprises treating with an activated gas the surface of a
transparent shaped article having a surface layer comprising a
finely divided particulate inorganic substance having an average
particle size of from about 1 to about 300 millimicrons dispersed
in said organic material, whereby the organic portion of the
surface layer is partially etched thereby forming the
anti-reflective layer.
19. A process for producing a transparent shaped article having an
enhanced anti-reflective effect, which comprises treating with an
activated gas the surface layer of a transparent shaped article
having a surface layer containing a finely divided particulate
inorganic substance having an average particle size of from about 1
to about 300 millimicrons whereby said activated gas partially
etches the surface layer of the transparent shaped article and
leaves said finely divided particulate inorganic substance
substantially unchanged in form and state to form the
anti-reflective layer.
Description
BACKGROUND OF THE INVENTION
(1) Field of the Invention
This invention relates to a process for imparting a lower
reflectance and a higher transmittance to a transparent shaped
article.
(2) Description of the Prior Art
Reduction of the reflectance of a transparent shaped article and
increase of the transmittance thereof are very important for
effective utilization of rays of light and elimination of blurring
of images occurring due to reflected images, and many methods have
heretofore been proposed for attaining the reduction of reflectance
and the increase of transmittance.
The principle of these proposed methods resides in that an optical
thin film composed mainly of an inorganic substance having a
refractive index different from that of a substrate is formed on
the surface of the transparent substrate, to achieve reduction of
the reflectance and increase of the transmittance. As means for
enhancing this effect, there have been adopted a method in which a
plurality of thin films differing in the refractive index are
formed on a substrate by multi-coating procedures, a method in
which the thicknesses of respective thin films are varied depending
upon the wavelengths of corresponding rays of light, and a method
in which a so-called optically heterogeneous film is formed on the
surface of the transparent substrate, which film has a refractive
index continuously varying through the thickness thereof.
For example, in the case of the method where a single
anti-reflective thin film is formed on the surface of a substrate,
it has been admitted that it is preferable that the anti-reflective
thin film to be formed on the surface of the substrate be composed
of an inorganic substance having a refractive index as low as
possible, such as magnesium fluoride, and the optical thickness of
the anti-reflective thin film be adjusted to 1/4 of the wavelength
of the objective ray of light.
Substrates to which such anti-reflective thin film can be applied
are restricted by the process for forming the anti-reflective thin
film. The substate to which such anti-reflective thin film has been
most popularly applied is a glass substrate. The technique of
coating a thin film of an inorganic substance on the surface of
such a glass substrate is difficult to apply to other substrates of
different materials or of a large size because many limitations are
imposed.
As the above coating technique, there can be mentioned a vacuum
evaporation deposition method, a sputtering method for improving
the adhesion and an electron beam method. However, it is difficult
to apply these coating methods to plastic materials which have
recently been popularly used in the field of spectacle lenses and
to plastic films and sheets on which anti-reflective thin films can
advantageously be formed. Various problems arise when these coating
methods are applied especially to plastic materials having a
high-hardness coating formed thereon for improving the scratch
resistance.
More specifically, plastic materials are ordinarily poor in heat
resistance and they cannot resist the above-mentioned coating
process, and such troubles as thermal degradation, melting thermal
deformation and production of optical strain are often caused.
Furthermore, the adhesion is ordinarily poor in plastic materials.
These disadvantages are mainly due to the difference of the
expansion coefficient between a plastic material and an inorganic
substance to be coated thereon. If the adhesion is extremely
reduced when the plastic material is exposed to an elevated
temperature or a high humidity, cracks and other defects are often
formed on the inorganic substance coating layer.
A more serious problem is how to eliminate a phenomenon in which
the impact resistance and flexibility of a plastic material are
drastically reduced by formation of such an inorganic substance
coating layer. Namely, the superiority of plastic materials to
glass materials is lost by the presence of such coating, and this
is quite a serious problem.
SUMMARY OF THE INVENTION
It is, therefore, a primary object of the present invention to
provide a process in which a transparent material exhibiting an
enhanced anti-reflective effect can be produced without
difficulty.
Another object and advantages of the present invention will be
apparent from the following description.
In accordance with the present invention, there is provided a
process for producing a transparent shaped article having an
enhanced anti-reflective effect, which comprises treating with an
activated gas, the surface of a transparent shaped article having a
surface layer containing a finely divided particulate inorganic
substance having an average particle size of about 1 to about 300
milli-microns.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The term "activating gas" used herein means a gas containing an
ion, an electron and/or an excited gas, formed under normal
pressure or reduced pressure. As means for generating such
activated gas, there can be employed corona discharge and direct
current, low frequency, high frequency or micro-wave high voltage
discharge under reduced pressure. As the gas source used for the
production of the activated gas, oxygen, air, nitrogen, argon and
Freon (a fluorinated hydrocarbon) are preferably used.
The finely divided particulate inorganic substance that is used in
the present invention has an average particle size of about 1 to
about 300 milli-microns, preferably about 5 to about 200
milli-microns, and it is required that no substantial change of the
form and state should be caused in the finely divided particulate
inorganic substance by the activated gas treatment described
hereinafter or, if any change is caused by the activated gas
treatment, such change of the form and state is very small. It does
not matter if parts or all of the fine particles are chemically
changed by the activated gas treatment, but the form and state
should be retained to such an extent that the intended effect of
the present invention can be attained.
It is difficult to prepare particles having too small a particle
size, and the use of particles having too large a particle size
results in a reduction of the transparency and makes it impossible
to attain the intended anti-reflective effect of the present
invention. Accordingly, particles having a particle size falling
within the above-mentioned range are used.
The fact that the form and shape of fine particles are not
substantially changed by the activated gas treatment, or such
change is very small, means that the form and shape of the fine
particles are retained to such an extent that micropores formed by
the activated gas treatment do not nullify the anti-reflective
effect.
Even fine shallow dents and the like are included in the micropores
referred to herein. The mechanism of manifesting the
anti-reflective effect in the present invention has not been
elucidated completely. However, the following presumption may be
made.
In the case where micropores (having a refractive index
substantially close to 1.00) are present homogeneously in the
finely divided particulate inorganic substance, a thin layer formed
of the micropores and particles present in such state will attain
an effect that will probably be attained when an imaginary
anti-reflective layer having a very low refractive index is formed.
This presumption is in agreement with the fact that a similar
effect can be obtained when a dispersion of fine particles is
coated on a substrate to form a corresponding thin layer, although
a problem, such as insufficient adhesion, is actually left unsolved
in this case.
Any inorganic substance satisfying the above requirements can be
used in the present invention and inorganic substances including
organic substituents may also be used. However, the properties and
kinds of inorganic substances should be determined according to not
only the intended anti-reflective effect, but also according to
other properties required. Oxides and halides of elements of the
Groups II, III, IV and V of the Periodic Table are preferably used
as the inorganic substance.
More specifically, fine particles of zinc oxide, silicon oxide,
aluminum oxide, titanium oxide, zirconium oxide, tin oxide,
beryllium chloride and antimony oxide are preferably used. Among
them, fine particles of silicon oxide and aluminum oxide are
especially preferred. These finely divided particulate inorganic
substances may be used alone or in the form of a mixture of two or
more.
The finely divided particulate inorganic substance should be
incorporated in the transparent material at least in the surface
layer portion thereof. As means for incorporating the finely
divided particulate inorganic substance, at least in the surface
layer portion of the transparent material, there may be adopted,
for example, a method in which the inorganic substance is uniformly
dispersed in the whole of the transparent material as the substrate
or selectively dispersed in the surface layer portion of the
transparent material prior to or during the step of shaping the
transparent material, and a method in which the inorganic substance
is dispersed in a transparent coating material and the dispersion
is coated on the surface of a transparent shaped article.
Dispersing of the finely divided particulate inorganic substance
can be accomplished by various known methods. For example, (a) a
method in which the finely divided particulate inorganic substance
is kneaded with the substrate (transparent material) under heating
or at room temperature in the presence or absence of a solvent and
other additive components, (b) a method in which the dispersion of
the finely divided particulate inorganic substance is mixed with
the substrate-constituting material (hereinafter referred to as
"vehicle component") in a volatile dispersion medium and then, the
volatile dispersion medium is evaporated, and (c) a method in which
the finely divided particulate inorganic substance is dispersed in
a monomer component and then, polymerization of the monomer
component is carried out.
When a coating material having the finely divided particulate
inorganic substance dispersed therein is used, it is preferred that
the above method (b) be adopted for the preparation of the
inorganic substance-dispersed coating material. In this case, it
sometimes happens that the coating film formed by evaporation of
the volatile dispersion medium is hardened. As the volatile
dispersion medium, there can be used, for example, water,
hydrocarbons, chlorinated hydrocarbons, esters, ketones, alcohols
and organic carboxylic acids. These dispersion media may be used
alone or in the form of a mixture of two or more.
The amount of the finely divided particulate inorganic substance
incorporated into the transparent material is 5 to 80% by weight,
preferably 10 to 70% by weight, in the surface layer portion to be
treated with the activated gas. Usually, the surface layer portion
to be treated with the activated gas has a thickness of up to 1
micron. If the amount is smaller than 5% by weight, no substantial
effect can be attained by incorporation of the finely divided
particulate inorganic substance, and, in contrast, if the amount is
larger than 80% by weight, formation of cracks and reduction of
transparency occur.
In the present invention, since it is desired to form a thin
surface layer having an anti-reflective effect by treating the
surface of the transparent material containing the finely divided
particulate inorganic substance, the shape, size and intended use
of the portion below this surface layer are not particularly
critical. Accordingly, it is not particularly significant which
method should be adopted for dispersing the finely divided
particulate inorganic substance into the transparent substrate
material, the method in which the inorganic substance is dispersed
in the coating material and the dispersion is coated on the
transparent substrate material (hereinafter referred to as "coating
method") or the method in which the inorganic substance is directly
dispersed in the substrate (transparent material). However, the
following advantage can be attained when the coating method is
adopted.
More specifically, in the case where the finely divided particulate
inorganic substance cannot easily be dispersed in the substrate or
properties of the substrate are adversely affected by dispersing
the finely divided particulate inorganic substance, if the
above-mentioned coating method is adopted, the anti-reflective
effect can be imparted conveniently to the substrate without
substantial influence on the properties of the substrate.
In dispersing the finely divided particulate inorganic substance,
the inorganic substance having a fine powdery form before
dispersing may be used, but in order to attain the intended object
of the present invention effectively, it is preferable that the
inorganic substance be used in the form of a colloidal dispersion
in a liquid dispersion medium.
The kind of the base material in which the finely divided
particulate inorganic substance is to be dispersed, that is, the
vehicle component, is not particularly critical, so far as a part
of or all of the base material is evaporated or extinguished by the
activated gas treatment to form a micropore-containing surface of
the inorganic substance. Ordinarily, organic group-containing
compounds of various elements, such as organic compounds and/or
organosilicon compounds, may be used, and high polymers of these
compounds are especially preferable. For example, there can be
mentioned epoxy resins, acrylic acid ester and/or methacrylic acid
ester copolymers (inclusive of copolymers with other vinyl
monomers), polyamides, polyesters (inclusive of so-called alkyd
resins and unsaturated polyester resins), amino resins (inclusive
of melamine resins and urea resins), urethane resins,
polycarbonates, polyvinyl acetate resins, polyvinyl alcohol resins,
styrene resins, transparent vinyl chloride resins, silicone resins,
cellulose type resins and diethylene glycol bisallyl carbonate
polymers (CR-39). Two or more of these resins may be used in
combination, and a cured product obtained by using an appropriate
curing agent may also be used. The vehicle component may further
contain a plasticizer, a curing agent and a curing catalyst, and
moreover, it may contain various additives such as a surface
controlling agent, an ultraviolet absorber and an antioxidant.
By the term "transparent material" referred to in the present
invention is meant a material having a haze value, defined by the
following formula, of at most 80%, and the material may be
colorless or may be colored with a pigment or dye: ##EQU1##
In order to enhance the intended effects of reducing the
reflectance and improving the transmittance, it is preferable that
a vehicle component having a high transparency be used. A silicone
type polymeric compound used as a coating material for improving
the surface hardness of a plastic article, or a polymeric compound
containing such silicone type polymeric compound is effectively
used as the vehicle component capable of manifesting not only the
surface hardness enhancing effect, but also the anti-reflective
effect. A composition comprising the above-mentioned polymeric
compound and a dispersion of silicon oxide type fine particles in
an alcoholic solvent and/or an aqueous solvent is especially
valuable as the material capable of simultaneously manifesting the
surface hardness-improving effect and the effect of improving the
transmittance in the case where a transparent material having an
especially high transmittance is desired.
Various methods have heretofore been proposed for forming coating
films of silicone type polymers. Among these known methods, there
is most effectively used, a method using a product formed by curing
a member selected from compounds represented by the following
general formula and hydrolysis products thereof:
wherein R.sup.1 and R.sup.2 stand for an alkyl, aryl, halogenated
alkyl, halogenated aryl or alkenyl group having 1 to 10 carbon
atoms or an organic group including an epoxy, methacryloxy,
acyloxy, mercapto, amino or cyano group, each of R.sup.1 and
R.sup.2 is bonded to the silicon atom by the Si-C linkage, R.sup.3
stands for an alkyl, alkoxyalkyl or acyl group having 1 to 4 carbon
atoms, a and b are numbers of 0, 1 or 2, and the sum of a plus b is
1 or 2.
As examples of such organic silicon compounds, there can be
mentioned trialkoxysilanes and triacyloxysilanes such as
methyltrimethoxysilane, methyltriethoxysilane,
methyltrimethoxyethoxysilane, methyltriacetoxysilane,
methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane,
vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane,
vinyltrimethoxyethoxysilane, phenyltrimethoxysilane,
phenyltriethoxysilane, phenyltriacetoxysilane,
.gamma.-chloropropyltrimethoxysilane,
.gamma.-chloropropyltriethoxysilane,
.gamma.-chloropropyltriacetoxysilane,
3,3,3-trifluoropropyltrimethoxysilane,
.gamma.-glycidoxypropyltrimethoxysilane,
.gamma.-glycidoxypropyltriethoxysilane,
.gamma.-(.beta.-glycidoxyethoxy)propyltrimethoxysilane,
.beta.-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,
.beta.-(3,4-epoxycyclohexyl)ethyltriethoxysilane,
.gamma.-methacryloxypropyltrimethoxysilane,
.gamma.-aminopropyltrimethoxysilane,
.gamma.-aminopropyltriethoxysilane,
.gamma.-mercaptopropyltrimethoxysilane,
.gamma.-mercaptopropyltriethoxysilane,
N-(.beta.-aminoethyl)-.gamma.-aminopropyltrimethoxysilane and
.beta.-cyanoethyltriethoxysilane; and dialkoxysilanes and
diacyloxysilanes such as dimethyldimethoxysilane,
phenylmethyldimethoxysilane, dimethyldiethoxysilane,
phenylmethyldiethoxysilane,
.gamma.-glycidoxypropylmethyldimethoxysilane,
.gamma.-glycidoxypropylmethyldiethoxysilane,
.gamma.-glycidoxypropylphenyldimethoxysilane,
.gamma.-glycidoxypropylphenyldiethoxysilane,
.gamma.-chloropropylmethyldimethoxysilane,
.gamma.-chloropropylmethyldiethoxysilane, dimethyldiacetoxysilane,
.gamma.-methacryloxypropylmethyldimethoxysilane,
.gamma.-methacryloxypropylmethyldiethoxysilane,
.gamma.-mercaptopropylmethyldimethoxysilane,
.gamma.-mercaptopropylmethyldiethoxysilane,
.gamma.-aminopropylmethyldimethoxysilane,
.gamma.-aminopropylmethyldiethoxysilane, methylvinyldimethoxysilane
and methylvinyldiethoxysilane.
These organic silicon compounds may be used alone or in the form of
a mixture of two or more. Various tetralkoxysilanes and
hydrolysates thereof may be used in combination with the
above-mentioned silane compounds, although they cannot be used
alone. As the tetraalkoxysilane, there can be mentioned, for
example, methyl silicate, ethyl silicate, n-propyl silicate,
i-propyl silicate, n-butyl silicate, sec-butyl silicate and t-butyl
silicate.
These organic silicon compounds can be cured even in the absence of
a catalyst. However, various curing catalysts heretofore proposed
may be used for promoting curing. For example, there can be used
metal salts, especially alkali metal salts, and ammonium salts, of
various acids and bases inclusive of Lewis acids and Lewis bases,
such as organic carboxylic acids, chromic acid, hypochlorous acid,
boric acid, bromic acid, selenious acid, thiosulfuric acid,
orthosilicic acid, thiocyanic acid, nitrous acid, aluminic acid and
carbonic acid, and alkoxides of aluminum, zirconium and titanium
and complexes thereof. Naturally, these compounds can be used in
combination with other organic substances, such as epoxy resins,
acrylic copolymers and vinyl copolymers. As such organic
substances, a hydroxyl group-containing polymer, for example,
polyvinyl alcohol is especially valuable.
When the above-mentioned composition is used as the coating
material, solvents and additives may be incorporated so as to
facilitate the coating operation and maintain a good storage
state.
When the above-mentioned composition is used as the coating
material, the substrate is coated with the composition. The kind of
the substrate is not particularly critical, so far as the intended
object of the present invention is attained. However, from the
viewpoint of the transparency, it is preferable that a glass
material or transparent plastic material be used as the substrate.
As the plastic material, there are preferably used polymethyl
methacrylate, methyl methacrylate copolymers, polycarbonates,
diethylene glycol bisallyl carbonate polymers (CR-39), polyesters,
especially polyethylene terephthalate, unsaturated polyesters and
epoxy resins. Coating, drying and/or curing can be accomplished
according to methods appropriately selected among the known methods
customarily adopted in the art of coating.
The transparent shaped article having an enhanced anti-reflective
effect may be in the form of a film, a sheet or various molded
articles. As such shaped articles, there can be mentioned, for
example, films or sheets used for window panes, greenhouses,
display cases, indication boards and gauge panelboards, and molded
articles such as for television covers, optical lenses and
spectacle lenses.
An anti-reflective thin film, the formation of which is one object
of the present invention, is obtained by treating with an activated
gas the surface portion of the transparent substrate or coated
material, which surface portion comprises as the main ingredients
the finely divided particulate inorganic substance and the vehicle
component for dispersing therein the finely divided particulate
inorganic substance.
In order to attain the objects of the present invention, an
activated gas obtained by direct current, low frequency, high
frequency or micro-wave high voltage discharge under a pressure of
10.sup.-2 to 10 Torr is especially preferable from the viewpoint of
the treatment efficiency. The so obtained activating gas is
so-called cold plasma, and the properties and generation methods of
such cold plasma are described in detail in "Chemistry of Cold
Plasma" (compiled by Keiichiro Hozumi and published by Nankodo,
Japan in 1976).
The activated gas treatment conditions may be varied depending upon
the shape and type of the treatment apparatus, the kind of the gas
used and the material, composition, shape and size of the surface
to be treated. Optimum conditions for attaining the objects of the
present invention most effectively can be readily determined based
on experiments. See Examples 1-30 which follow.
By the electron microscope observation, it has been confirmed that
the treated thin film manifesting the intended effects of the
present invention has micropores. Since the mechanism of the
present invention and the shape and distribution state of
micropores have not yet been elucidated sufficiently, the thickness
of the micropore-present film cannot be defined specifically.
However, it is believed that good results are obtained if the
thickness of the micropore-present film is up to 1000
milli-microns, preferably up to 500 milli-microns.
It is preferable that a protecting coating material is coated on
the surface of the substrate or coating material having the
anti-reflective film layer in order to improve the mechanical
properties and durability of the anti-reflective film layer.
The configuration of the so applied protecting coating material
varies depending upon the material used, the coating composition
(inclusive of the solvent) and the coating conditions, and it is
construed that in some cases, micropores present in the
anti-reflective film layer are partially filled with the protecting
coating material or in other cases, the protecting coating material
covers the anti-reflective layer without being introduced into
micropores. Ordinarily, it is considered that the protecting
coating material covers the micropores of the anti-reflective film
layer in both the above two states. An appropriate protecting
coating material is selected according to the relation to the lower
layer and the required durability. In the present invention, either
an inorganic material or an organic material can be used as the
protecting coating material. This protecting coating material is
applied in the form of a very thin layer. Accordingly, the
transparency of the protecting coating material is not
substantially important. However, from the viewpoint of the
transparency of the entire structure, it is preferable that the
protecting coating material be transparent. Materials mentioned
above as the vehicle component can be used as the protecting
coating material. Among them, from the viewpoint of improvement of
the durability, it is preferable to use a protecting coating
material containing a thermosetting resin. As the thermosetting
resin, there can be mentioned, for example, epoxy resins, acrylic
acid ester and/or methacrylic acid ester copolymers (inclusive of
copolymers with other vinyl monomers), polyester resins, alkyd
resins, unsaturated polyester resins and silicone type resins. Some
of these thermosetting resins are cured at room temperature or
under heating by themselves or with the aid of a catalyst, a ray of
light, a radioactive ray or a curing agent. A pigment or dye and
other additives may be incorporated into the thermosetting resin,
so far as the transparency is not reduced. The protecting coating
material is used and coated in the form of a dilute solution or
dispersion obtained by dissolving or dispersing the protecting
coating material in a volatile solvent. The concentration of the
coating material may be varied depending upon the particular resin
and solvent used and the anti-reflective film layer to be coated,
and the concentration should be adjusted so that the desired
coating amount is obtained. It is preferable that the amount of the
coating material be 5 mg to 1 g, especially 10 to 500 mg, per
m.sup.2 of the surface of the transparent shaped article to be
coated. If the amount coated is too small, no substantial
protecting effect for the anti-reflective film layer can be
obtained, and, in contrast, if the amount is too large, the
anti-reflective effect is substantially reduced.
A necessary amount of the coating material can be coated in one
coating operation, but the coating operation may be repeated
several times so that the coating material is coated in the
necessary amount as a whole. Furthermore, there may be adopted a
method in which a curing agent is first coated and a coating
material that can be cured by the curing agent is then coated, or
the order of coating of the curing agent and coating material can
be reversed.
Coating of the protecting coating material can be accomplished
according to any of the coating methods customarily adopted in the
field of coating, such as brush coating, dip coating, spin coating,
flow coating, spray coating, roller coating and curtain flow
coating. Furthermore, drying and/or curing can be performed
according to methods customarily adopted in the field of
coating.
The present invention will now be described in detail with
reference to the following Examples.
EXAMPLE 1 AND COMPARATIVE EXAMPLE 1
(1) Preparation of Hydrolyzed Silane
A reaction vessel equipped with a rotor was charged with 2,124 g of
.gamma.-glycidoxypropyltrimethoxysilane, and 486 g of a 0.01 N
aqueous solution of hydrochloric acid was gradually dropped to the
charge while maintaining the liquid temperature at 10.degree. C.
under agitation by a magnetic stirrer. Cooling was stopped after
completion of the dropwise addition. Thus, a hydrolyzed silane was
obtained.
(2) Preparation of Coating Solution
To 312.3 g of the hydrolyzed silane was added 600 g of colloidal
silica dispersed in methanol ("Methanol Silica Sol" manufactured by
Nissan Kagaku Kabushiki Kaisha and having a solid content of 30%
and an average particle size of 13.+-.1 m.mu. under agitation.
Then, 207.9 g of methanol, 60 g of diethylene glycol dimethyl ether
and 1.8 g of a silicone type surface active agent were added to the
dispersed liquid mixture, and 18 g of aluminum acetylacetonate was
further added and the mixture was sufficiently stirred to form a
coating solution.
(3) Coating, Treatment with Activated Gas and Evaluation
A diethylene glycol bisallyl carbonate polymer lens (plano-lens
CR-39 having a diameter of 75 mm and a thickness of 2.1 mm) was
dipped in an aqueous solution of sodium hydroxide and then washed.
Thereafter, the lens was coated with the above-mentioned coating
solution according to a dip coating method at a pull-out speed of
10 cm/min. The coating lens was heated and cured for 4 hours in a
hot air drier maintained at 93.degree. C. The coated lens was
subjected to the activated gas treatment according to the following
method. The total luminous transmittance was measured before and
after the activated gas treatment.
A low temperature ashing apparatus ("Model IPC 1003B" manufactured
by International Plasma Corporation) was used as the activated gas
treatment apparatus. The treatment was carried out at an output of
50 W and a gas flow rate of 50 ml/min. Other treatment conditions
and results of evaluation are shown in Table I, below. For
comparison, the above procedures were repeated without adding
colloidal silica dispersed in methanol. The obtained results are
also shown in Table I, below.
When the coated lens obtained in Example 1 was subjected to the
falling ball impact test according to FDA standards, no breakage of
the lens was observed. Furthermore, when this lens was heat-treated
at 120.degree. C. for 2 hours, no cracks were formed and no other
change was observed.
EXAMPLE 2
(1) Preparation of Coating Solution
A mixture of 27.8 g of an epoxy resin (sorbitol polyglycidyl ether
manufactured and sold under the tradename of "Denacol EX-614" by
Nagase Sangyo Kabushiki Kaisha), 48.5 g of methanol, 48.5 g of
methyl ethyl ketone, 1.38 g of dichlorodimethylurea and 0.84 g of
dicyandiamide was sufficiently stirred, and 92.7 g of the same
methanol silica sol as used in Example 1 was added to the above
mixture under agitation to form a coating solution.
(2) Coating, Activated Gas Treatment and Evaluation
Coating was carried out by using the so prepared coating solution
in the same manner as described in Example 1. Curing was conducted
at 130.degree. C. for 2 hours.
The activated gas treatment and evaluation of the coated lens were
carried out in the same manner as in Example 1. The treatment
conditions and evaluation results are shown in Table I, below.
EXAMPLE 3 AND COMPARATIVE EXAMPLE 2
(1) Preparation of Acrylic Resin
A flask equipped with a stirrer was charged with 100 g of n-propyl
alcohol, and the temperature was elevated to 90.degree. to
95.degree. C.
After elevation of the temperature, a mixed solution having the
following composition, which was prepared separately, was dropped
to the charge in the flask over a period of 2 hours.
______________________________________ Mixed Solution:
______________________________________ (a) Acrylic Acid 4 g (b)
Hydroxyethyl methacrylate 16 g (c) Ethyl acrylate 45 g (d) Methyl
methacrylate 35 g (e) n-Dodecylmercaptan 2.0 g (f)
Azobisisobutyronitrile 1.0 g
______________________________________
After completion of the dropwise addition, 0.2 g of
azobisisobutyronitrile was added every 30 minutes over a period of
two hours, four times in all. After the final addition of
azobisisobutyronitrile, heating was continued for 1 hour to form an
acrylic resin solution.
(2) Preparation of Coating Solution
To 64 g of the so formed acrylic resin solution were added 9 g of a
melamine resin ("Cymel 370" manufactured by Mitsui Toatsu Kagaku
Kabushiki Kaisha), 80 g of ethylene chlorohydrin and 47 g of
n-propyl alcohol, and the mixture was sufficiently stirred. Then,
133.4 g of colloidal silica sol dispersed in n-propanol (having a
solid content of 30% and an average particle size of 13.+-.1 m.mu.
were added under agitation to the liquid mixture to form a coating
solution.
(3) Coating, Activated Gas Treatment and Evaluation
Coating was carried out by using the so prepared coating solution
in the same manner as described in Example 1. Curing was conducted
at 130.degree. C. for 2 hours.
The activated gas treatment and evaluation of the coated lens were
carried out in the same manner as in Example 1. Treatment
conditions and results of evaluation are shown in Table I, below.
For comparison, the above procedures were repeated without addition
of the silica sol. The obtained results are shown in Table I,
below.
EXAMPLE 4 AND COMPARATIVE EXAMPLE 3
(1) Preparation of Acrylic Resin
An acrylic resin was prepared in the same manner as described in
Example 3 except that a mixed monomer solution having the following
composition was used.
______________________________________ Mixed Solution:
______________________________________ (a) Acrylic Acid 12 g (b)
Hydroxyethyl methacrylate 16 g (c) Ethyl acrylate 45 g (d) Methyl
methacrylate 27 g (e) n-Dodecylmercaptan 2.0 g (f)
Azobisisobutyronitrile 1.0 g
______________________________________
(2) Preparation of Coating Solution
A coating solution was prepared by using the so prepared acrylic
resin in the same manner as in Example 3.
(3) Coating, Activated Gas Treatment and Evaluation
The coating treatment, activated gas treatment and evaluation were
carried out in the same manner as described in Example 3. The
treatment conditions and evaluation results are shown in Table I,
below. For comparison, the above procedures were repeated without
addition of the silica sol. The obtained results are shown in Table
I, below.
EXAMPLE 5 AND COMPARATIVE EXAMPLE 4
(1) Preparation of Hydrolyzed Silane
A reaction vessel equipped with a rotor was charged with 386.3 g of
.gamma.-glycidoxypropylmethyldiethoxysilane, and 55.8 g of a 0.05 N
aqueous solution of hydrochloric acid was added dropwise to the
charge under agitation by a magnetic stirrer while maintaining the
liquid temperature at 10.degree. C. After completion of the
dropwise addition, cooling was stopped to obtain hydrolyzed
silane.
(2) Preparation of Coating Solution
To 61.2 g of the so prepared hydrolyzed silane was added under
agitation 125.0 g of the same methanol silica sol as used in
Example 1. Then, 50.4 g of methanol, 9.3 g of diethylene glycol
dimethyl ether and 0.4 g of a silicone type surfactant were added
to the mixed dispersed liquid, and 7.02 g of aluminum
acethylacetonate was further added and the mixture was sufficiently
stirred to form a coating solution.
(3) Coating, Activated Gas Treatment and Evaluation
The coating treatment was carried out by using the so prepared
coating solution in the same manner as in Example 1, and the
activated gas treatment and evaluation were conducted in the same
manner as in Example 1. The treatment conditions and evaluation
results are shown in Table I, below. For comparison, the above
procedures were repeated without addition of the methanol silica
sol. The obtained results are shown in Table I, below.
EXAMPLE 6
(1) Preparation of Coating Solution
In 270 g of ethylene chlorohydrin was dissolved 30 g of cellulose
acetate butyrate ("EAB-555-0.2" manufactured by Nagase Sangyo
Kabushiki Kaisha), and 100 g of the same methanol silica sol as
used in Example 1 was added to the solution and the mixture was
stirred to form a coating solution.
(2) Coating, Activated Gas Treatment and Evaluation
The coating treatment was carried out by using the so prepared
coating solution in the same manner as described in Example 1.
Curing was conducted at 130.degree. C. for 2 hours.
The activated gas treatment and evaluation of the coated lens were
conducted in the same manner as described in Example 1. The
treatment conditions and evaluation results are shown in Table I,
below.
EXAMPLE 7 AND COMPARATIVE EXAMPLE 5
(1) Preparation of Coating Solution
To 441.8 g of hydrolyzed
.gamma.-glycidoxypropylmethyldiethoxysilane prepared in Example 5
was added 207.7 g of .gamma.-chloropropyltrimethoxysilane, and 56.5
g of a 0.01 N aqueous solution of hydrochloric acid was gradually
dropped to the mixture under agitation while maintaining the liquid
temperature at 10.degree. C. After completion of the dropwise
addition, cooling was stopped. Then, 1354.3 g of the same methanol
silica sol as used in Example 1, 103 g of diethylene glycol
dimethyl ether, 791.6 g of methanol and 4.5 g of a silicone type
surface active agent were added to 606 g of the so obtained
hydrolysis product under agitation. Then, 40.6 g of aluminum
acetylacetonate was further added to the mixture, and the resulting
mixture was stirred to form a coating solution.
(2) Coating, Activated Gas Treatment and Evaluation
The coating treatment was carried out by using the so prepared
coating solution in the same manner as in Example 1, and the
activated gas treatment and evaluation were conducted in the same
manner as described in Example 1. The treatment conditions and
evaluation results are shown in Table I, below.
When the surface layer portion of the activated gas-treated lens
was observed through an electron microscope (90,000 magnification),
it was found that the surface was irregular and micropores were
present in the surface portion over a depth of 1,000 A from the top
face.
For comparison, the above procedures were repeated without addition
of the methanol silica sol. The obtained results are shown in Table
I, below.
EXAMPLE 8
(1) Preparation of Coating Solution
To 30.6 g of hydrolyzed .gamma.-glycidoxypropylmethyldiethoxysilane
prepared in Example 5 was added 38.0 g of methyltrimethoxysilane,
and the liquid temperature was maintained at 10.degree. C. Then,
15.1 g of a 0.01 N aqueous solution of hydrochloric acid was
gradually dropped to the mixture under agitation. After completion
of the dropwise addition, cooling was stopped. Then, 125 g of the
same methanol silica sol as used in Example 1, 26.7 g of methanol,
10.4 g of diethylene glycol dimethyl ether and 0.4 g of a silicone
type surface active agent were added to 83.7 g of the hydrolysis
product, and the mixture was stirred and 3.75 g of aluminum
acetylacetonate was further added. The mixture was sufficiently
mixed to form a coating solution.
(2) Coating, Activated Gas Treatment and Evaluation
The coating treatment was carried out by using the so prepared
coating solution in the same manner as described in Example 1, and
the activated gas treatment and evaluation were conducted in the
same manner as described in Example 1. The treatment conditions and
evaluation results are shown in Table I, below.
EXAMPLE 9
(1) Preparation of Coating Solution
A reaction vessel was charged with 83.1 g of
.gamma.-glycidoxypropylmethyldiethoxysilane and 44.7 g of
phenyltrimethoxysilane, and the liquid temperature was maintained
at 10.degree. C. Then, 24.3 g of a 0.05 N aqueous solution of
hydrochloric acid was gradually dropped to the mixture under
agitation. After completion of the dropwise addition, cooling was
stopped, and 291.8 g of the same methanol silica sol as used in
Example 1, 46.6 g of methanol and 0.75 g of a silicone type surface
active agent were added to the so formed hydrolysis product under
agitation. Then, 8.75 g of aluminum acetylacetonate was added to
the liquid mixture, and the mixture was stirred to form a coating
solution.
(2) Coating, Activated Gas Treatment and Evaluation
The coating treatment was carried out by using the so prepared
coating solution in the same manner as described in Example 1, and
the activated gas treatment and evaluation were conducted in the
same manner as described in Example 1. The treatment conditions and
evaluation results are shown in Table I, below.
EXAMPLE 10
(1) Preparation of Coating Solution
To 442.1 of hydrolyzed .gamma.-glycidoxypropylmethyldiethoxysilane
prepared in Example 5 were added 155.4 g of an epoxy resin
("Epikote 827" manufactured by Shell Kagaku Kabushiki Kaisha),
223.8 g of diacetone alcohol and 111.6 g of benzyl alcohol, and the
mixture was stirred to form a homogeneous solution.
Then, 1,423 of the same methanol silica sol as used in Example 1,
597.5 g of methanol and 3.84 g of a silicone type surface active
agent were added to the solution, and the mixture was sufficiently
stirred. Then, 42.7 g of aluminum acetylacetonate was added to the
liquid mixture, and the mixture was stirred to form a coating
solution.
(2) Coating, Activated Gas Treatment and Evaluation
The coating treatment was carried out by using the so prepared
coating solution in the same manner as described in Example 1, and
the activated gas treatment and evaluation were conducted in the
same manner as described in Example 1. The treatment conditions and
evaluation results are shown in Table I, below.
EXAMPLES 11 THROUGH 13
(1) Preparation of Coating Solution
To 310.0 g of the hydrolyzed silane prepared in Example 7 were
added 20 g of "Epiclon 750" (manufactured by Dainihon Ink Kagaku
Kabushiki Kaisha), 39.6 g of diacetone alcohol, 130.4 g of
methanol, 20 g of benzyl alcohol, 660.0 g of the same methanol
silica sol as used in Example 1 and 1.8 g of a silicone type
surfactant under agitation. Then 20 g of aluminum acetylacetonate
was added to the liquid mixture, and the mixture was stirred to
form a coating solution.
(2) Coating, Activated Gas Treatment and Evaluation
The coating treatment was carried out by using the so prepared
coating solution in the same manner as described in Example 1, and
the activated gas treatment and evaluation were conducted in the
same manner as described in Example 1. The treatment conditions and
evaluation results are shown in Table I, below.
EXAMPLES 14 THROUGH 16
(1) Preparation of Coating Solution
To 442.1 g of the hydrolyzed silane prepared in Example 5 were
added 97.3 g of an epoxy resin ("Epikote 827" manufactured by Shell
Kagaku Kabushiki Kaisha), 58.9 g of "Epikote 834" (manufactured by
Shell Kagaku Kabushiki Kaisha), 77.7 g of "Denacal EX-320"
(trimethylolpropane polyglycidyl ether manufactured by Nagase
Sangyo Kabushiki Kaisha), 235.4 g of diacetone alcohol, 118.6 g of
benzyl alcohol and 4.2 g of a silicone type surfactant, and the
mixture was stirred to form a solution. Then, 1,678.6 g of the same
methanol silica sol as used in Example 1 was added to the solution
under agitation. Then, 50.6 g of aluminum acetylacetonate was added
to the dispersed liquid mixture, and the mixture was stirred to
form a coating solution.
(2) Coating, Activated Gas Treatment and Evaluation
A polycarbonate lens ("Rexan-141" manufactured by General Electric
Co. and having a diameter of 60 mm and a thickness of 3.0 mm) was
dip-coated with the so prepared coating solution at a pull-out
speed of 10 cm/min. The coated lens was heated and cured for 2
hours in a hot air drier maintained at 130.degree. C.
The activated gas treatment and evaluation of the coated lens were
conducted in the same manner as described in Example 1. The
treatment conditions and evaluation results are shown in Table I,
below.
EXAMPLES 17 THROUGH 19
(1) Preparation of Hydrolyzed
.beta.-(3,4-epoxycyclohexyl)ethyltrimethoxysilane
A reaction vessel equipped with a rotor was charged with 168 g of
.beta.-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and while the
liquid temperature was maintained at 20.degree. C. under agitation
by a magnetic stirrer, 37.2 of a 0.01 N aqueous solution of
hydrochloric acid was gradually dropped to the charge. After
completion of the dropwise addition, agitation was stopped to
obtain hydrolyzed
.beta.-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.
(2) Preparation of Coating Solution
To 394.4 g of hydrolyzed
.gamma.-glycidoxypropylmethyldiethoxysilane prepared in Example 5
was added 205.2 g of the so prepared hydrolyzed
.beta.-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and a solution
comprising 24.8 g of "Epikote 827", 64.6 g of "Shodyne 508"
(diglycidyl phthalate epoxy resin manufactured by Showa Denko
Kabushiki Kaisha), 385 g of benzyl alcohol, 96.2 g of acetylacetone
and 4.8 g of a silicone type surfactant, which was prepared
separately, was added to the above liquid mixture. Then, 1,962 g of
the same methanol silica sol as used in Example 1 was added to the
liquid mixture, and 73.4 g of aluminum acetylacetonate was further
added and the mixture was stirred to form a coating solution.
(3) Coating, Activated Gas Treatment and Evaluation
A lens prepared by injection molding of polymethyl methacrylate
("Acrypet" manufactured by Mitsubishi Rayon Kabushiki Kaisha and
having a diameter of 75 mm and a thickness of 1.8 mm) was
dip-coated with the so prepared coating solution at a pull-out
speed of 10 cm/min, and the coated lens was cured for 2 hours in a
hot air drier maintained at 97.degree. C.
The activated gas treatment and evaluation of the coated lens were
conducted in the same manner as described in Example 1. The
treatment conditions and evaluation results are shown in Table I,
below.
EXAMPLE 20
(1) Preparation of Coating Solution
To 46.87 g of the hydrolyzed silane prepared in Example 1 were
added 85.51 g of an alumina sol ("Alumina Sol 200" manufactured by
Nissan Kagaku Kabushiki Kaisha and having a solid content of 13.5%
and an average particle size of 100 m.mu..times.10 m.mu.), 6.62 g
of ethylene chlorohydrin, 0.2 g of a silicone type surfactant and
1.93 g of aluminum acetylacetonate, and the mixture was
sufficiently strirred to form a coating solution.
(2) Coating, Activated Gas Treatment and Evaluation
The coating treatment was carried out by using the so prepared
coating solution in the same manner as in Example 1, and the
activated gas treatment and evaluation were conducted in the same
manner as described in Example 1. The treatment conditions and
evaluation results are shown in Table I, below.
EXAMPLE 21
(1) Preparation of Coating Solution
To 331.9 g of hydrolyzed
.gamma.-glycidoxypropylmethyldiethoxysilane prepared in the same
manner as described in Example 5 was added a solution having the
following composition, which was prepared separately.
______________________________________ (a) Epikote 827 87.95 g (b)
Epikote 834 21.99 g (c) Denacol EX-320 65.97 g (d) Benzyl alcohol
136.70 g ______________________________________
To the resulting mixed solution were added 227.87 g of diacetone
alcohol, 223.31 g of n-butanol, 84.32 g of acetylacetone, 3.94 g of
a silicone type surfactant, 1,770.5 g of methanol silica sol and
45.53 g of aluminum acetylacetonate, and the mixture was
sufficiently stirred to form a coating solution.
(2) Coating, Activated Gas Treatment and Evaluation
A polycarbonate lens (plano-lens having a diameter of 65 mm and a
thickness of 1.8 mm) was coated with the so prepared coating
solution in the same manner as described in Example 1. Curing was
conducted at 130.degree. C. for 2 hours.
The activated gas treatment and evaluation of the coated lens were
conducted in the same manner as described in Example 1. The
treatment conditions and evaluation results are shown in Table I,
below.
EXAMPLE 22
(1) Preparation of Hydrolyzed Silane
A reaction vessel equipped with a rotor was charged with 38.0 g of
methyltrimethoxysilane, 28.8 g of phenyltrimethoxysilane and 12.5 g
of acetic acid, and 22.9 g of a 0.01 N aqueous solution of
hydrochloric acid was gradually dropped to the mixture under
agitation by a magnetic stirrer while maintaining the liquid
temperature at 10.degree. C. After completion of the dropwise
addition, cooling was stopped to obtain a hydrolyzed silane.
(2) Preparation of Coating Solution
To 51.2 g of the so prepared hydrolyzed silane were added 77.0 g of
colloidal silica dispersed in ethylene chlorohydrin (having a solid
contnet of 24.3% and an average particle size of 13.+-.1 m.mu.),
6.4 g of diethylene glycol dimethyl ether, 0.2 g of a silicone type
surfactant and 0.34 g of sodium acetate, and the mixture was
sufficiently stirred to form a coating solution.
(3) Coating, Activated Gas Treatment and Evaluation
Coating was carried out by using the so prepared coating solution
in the same manner as described in Example 1. Curing was conducted
at 130.degree. C. for 2 hours.
The activated gas treatment and evaluation of the coated lens were
conducted in the same manner as described in Example 1. The
treatment conditions and evaluation results are shown in Table I,
below.
EXAMPLE 23
A diethylene glycol bisallyl carbonate polymer sheet ("CR-39" sheet
having a thickness of 2.0 mm) was coated with the coating solution
prepared in Example 10 in the same manner as described in Example
1, and the sheet was subjected to the same activating gas treatment
as described in Example 1. The treatment conditions and results of
evaluation of the resulting coated sheet are shown in Table I,
below.
EXAMPLE 24
(1) Preparation of Hydrolyzed Silane
A reaction vessel equipped with a rotor was charged with 112.6 g of
.gamma.-glycidoxypropylmethyldiethoxysilane and 60.8 g of
.gamma.-chloropropyltrimethoxysilane, and while the liquid
temperature was maintained at 10.degree. C. under agitation by a
magnetic stirrer, 33 g of a 0.05 N aqueous solution of hydrochloric
acid was gradually dropped to the charge. After completion of the
dropwise addition, cooling was stopped to obtain a hydrolyzed
silane.
(2) Preparation of Coating Solution
To 154.8 g of the so prepared hydrolyzed silane was added 330 g of
the same methanol silica sol as used in Example 1 under agitation.
Then 10.1 g of "Epiclon 750" (manufactured by Dainihon Ink Kagaku
Kabushiki Kaisha), 19.8 g of diacetone alcohol, 10.1 g of benzyl
alcohol, 64.5 g of methanol and 1 g of a silicone type surfactant
were added to the liquid mixture, and the mixture was sufficiently
stirred. Then, 10 g of aluminum acetylacetonate were added to the
mixture, and the resulting mixture was sufficiently stirred to form
a coating solution.
(3) Coating, Activated Gas Treatment and Evaluation
A polyethylene terephthalate film (manufactured and sold under the
tradename of "Lumilar T-125 Sand Mat" by Toray Industries Inc.) was
coated with the so prepared coating solution. Coating and curing
were conducted in the same manner as described in Example 14. The
activated gas treatment and evaluation were conducted in the same
manner as described in Example 1. The treatment conditions and
evaluation results are shown in Table I, below.
TABLE I ______________________________________ Activated Gas
Treatment Conditions Total Luminous Trans- Time mittance (%) Run
(min- Before After No. Example No. utes) Gas Treatment Treatment
______________________________________ 1 Example 1 3 Oxygen 92.76
97.28 Comp. Ex. 1 3 Oxygen 92.28 92.08 2 Example 2 0.5 Oxygen 92.04
96.80 3 Example 3 0.5 Oxygen 92.62 97.45 Comp. Ex. 2 0.5 Oxygen
92.20 92.48 4 Example 4 0.5 Oxygen 92.68 97.37 Comp. Ex. 3 0.5
Oxygen 92.05 92.28 5 Example 5 5 Oxygen 93.01 97.62 Comp. Ex. 4 5
Oxygen 92.58 92.66 6 Example 6 0.5 Oxygen 90.34 96.30 7 Example 7
10 Oxygen 92.89 97.30 Comp. Ex. 5 10 Oxygen 92.69 92.34 8 Example 8
3 Oxygen 93.16 95.58 9 Example 9 3 Oxygen 92.31 97.98 10 Example 10
1 Oxygen 92.33 98.50 11 Example 11 3 Oxygen 92.55 98.80 12 Example
12 3 Nitrogen 92.60 94.28 13 Example 13 5 Air 92.60 97.87 14
Example 14 1 Oxygen 88.55 94.44 15 Example 15 3 Nitrogen 89.04
95.51 16 Example 16 3 Air 89.04 95.86 17 Example 17 1 Oxygen 92.28
97.61 18 Example 18 3 Nitrogen 92.70 97.83 19 Example 19 3 Air
92.70 98.82 20 Example 20 3 Oxygen 87.53 90.77 21 Example 21 3
Oxygen 93.10 97.06 22 Example 22 5 Oxygen 92.62 94.51 23 Example 23
1 Oxygen 92.40 98.71 24 Example 24 2.8 Oxygen 72.90 74.89
______________________________________
COMPARATIVE EXAMPLE 6
An inorganic oxide composed mainly of SiO and SiO.sub.2 was coated
in a thickness of 1.5 microns by vacuum evaporation deposition on a
diethylene glycol bisallyl carbonate polymer lens (plano-lens
having a diameter of 70 mm and a thickness of 2.1 mm) to obtain an
anti-reflective lens. The total luminous transmittance of the
obtained lens was 96.0%. When the lens was subjected to the falling
ball impact test according to FDA standards, the lens was destroyed
in contrast to the lens in Example 1.
When the above anti-reflective lens was heated in an oven
maintained at 70.degree. C., many cracks were formed on the surface
of the lens.
EXAMPLE 25 AND COMPARATIVE EXAMPLE 7
(1) Preparation of Hydrolyzed Silane
A reaction vessel equipped with a rotor was charged with 84.6 g of
.gamma.-glycidoxypropylmethyldiethoxysilane and 45.8 g of
phenyltrimethoxysilane, and 24.6 g of a 0.05 N aqueous solution of
hydrochloric acid was gradually dropped to the charge while
maintaining the liquid temperature at 10.degree. C. under agitation
by a magnetic stirrer. Agitation was continued after completion of
the dropwise addition. Thus, the reaction was conducted for about
40 minutes, and a hydrolyzed silane was obtained.
(2) Preparation of Coating Solution
A liquid mixture of 10 g of an epoxy resin ("Epiclon 750"
manufactured and sold by Dainihon Ink Kagaku Kabushiki Kaisha), 10
g of benzyl alcohol, 19.8 g of diacetone alcohol and 0.9 g of a
silicon type surfactant was added to the above-mentioned hydrolyzed
silane under agitation. Then, 330 g of colloidal silica in
methanol, similar to that used in Example 1, 10 g of aluminum
acetylacetonate and 65.2 g of methanol were added to the mixture in
this order. Then, the mixture was sufficiently stirred to form a
coating solution.
(3) Coating and Treatment with Activated Gas
A diethylene glycol bisallyl carbonate polymer lens (plano-lens
CR-39 was having a diameter of 71 mm and a thickness of 2.1 mm) was
dipped in an aqueous solution of sodium hydroxide and then washed.
Thereafter, the lens was coated with the above-mentioned coating
solution according to a dip coating method at a pull-out speed of
10 cm/min. The coated lens was preliminarily heated at 82.degree.
C. for 10 minutes and then cured for 4 hours in a hot air drier
maintained at 93.degree. C. The coated lens was subjected to the
activated gas treatment according to the following method.
A low temperature ashing apparatus (Model IPC 1003B manufactured by
International Plasma Corporation) was used as the activated gas
treatment apparatus. The treatment was carried out at an output of
50 W and an oxygen flow rate of 50 ml/min for 210 seconds. The
total luminous transmittance, which was 92.4% before the treatment,
was increased to 98.3% by this treatment.
(4) Preparation and Coating of Protecting Coating Material
14.2 g of .gamma.-glycidoxypropyltrimethoxysilane was hydrolyzed at
10.degree. C. in the same manner as described in preceding
paragraph (1) by using a 0.01 N aqueous solution of hydrochloric
acid. Then, 984 g of methanol and 0.5 g of aluminum acetylacetonate
were added to the hydrolysis product and the mixture was
sufficiently stirred. A protecting coating layer was formed on the
anti-reflective lens, which was obtained in preceding paragraph
(3), by using the so formed coating material. The pull-out speed
adopted for the coating operation was 10 cm/min. The coated lens
was preliminarily heated at 82.degree. C. for 10 minutes and then
cured at 93.degree. C. for 2 hours.
The obtained lens had a total luminous transmittance of 96.7% and
an anti-reflective effect. Properties of the so obtained lens and
the lens having no protecting coating as a comparative lens are
shown in Table II, below. From the results shown in Table II, it
will readily be understood that the mechanical strength and
durability can be improved by the protective coating.
TABLE II ______________________________________ Lens Having Lens
Having No Protective Coating Protective Coating
______________________________________ Total Luminous 96.7 98.3
transmittance (%) Surface hardness*.sup.1 Scratched to a
Anti-reflective surface (steel wool) negligible extent layer
separated Adhesion*.sup.2 (room Not changed Not changed
temperature) (after dipping in Not changed Anti-reflective surface
hot water at 70.degree. C. layer separated for 1 hour)
______________________________________ Note *.sup.1 Abrasive test
with steel wool #0000 under a load of 1.5 Kg was conducted 10
times. *.sup.2 Square cuts (10 .times. 10) having a size of 1 mm
were formed by safety razor blade and an adhesive tape was applied
to these square cuts and then peeled.
EXAMPLE 26 AND COMPARATIVE EXAMPLE 8
A lens sample was prepared in the same manner as described in
Example 25. A mixture of 84.4 g of
.gamma.-glycidoxypropylmethyldiethoxysilane and 45.6 g of
.gamma.-chloropropyltrimethoxysilane was hydrolyzed with 24.8 g of
0.05 N hydrochloric acid. A coating solution was prepared by adding
the following components to the hydrolysis product.
______________________________________ Epiclon 750 10.1 g Methanol
silica sol 330.0 g Diacetone alcohol 19.8 g Benzyl alcohol 10.1 g
Silicone type surfactant 0.9 g Aluminum acetylacetonate 10.1 g
Methanol 64.5 g ______________________________________
The sample was coated with the above coating solution and then
cured in the same manner as described in Example 25 and the coated
sample was treated at an oxygen flow rate of 100 ml/min and an
output of 50 W for 20 minutes by using a surface-treating plasma
apparatus ("Model PR 501A" manufactured by Yamato Kagaku Kabushiki
Kaisha).
A protective coating was formed on the treated sample in the same
manner as described in Example 25 by using a coating composition
comprising 3.46 g of a product obtained by hydrolyzing
.gamma.-glycidoxypropyltrimethoxysilane (2.82 g) with 0.01 N
hydrochloric acid (0.64 g), 0.008 g of a silicone type surfactant
and 396.5 g of n-propanol.
Properties of the so prepared lens and the comparative lens having
no protecting coating are shown in Table III, below.
TABLE III ______________________________________ Lens Having Lens
Having No Protecting Protecting Coating Coating
______________________________________ Total Luminous 97.0% 98.5%
transmittance Surface hardness Scratched to a Anti-reflective
surface (steel wool) negligible extent layer separated Adhesion Not
changed Not changed (room temperature) (After dipping in Not
changed Anti-reflective surface hot water at 70.degree. C. layer
peeled off for 1 hour) Framing test*.sup.1 Not changed Grip marks
left on lens Outdoor exposure Not changed Anti-reflective surface
(2 months in layer partially separated Florida)
______________________________________ Note: *.sup.1 The lens was
cut by a Takubo automatic diamond lens edger.
EXAMPLE 27
An anti-reflective lens was prepared according to the method
described in Example 25 or 26, and a protecting coating material
shown in Table IV, below, was coated on the lens. Each coated lens
was found to have a durability improved over the durability of the
comparative lens having no protecting coating. Each protecting
coating material contained aluminum acetylacetonate as a catalyst
in an amount of 5% by weight based on the total solids in addition
to the components shown in Table IV. The silane compound was used
after it had been hydrolyzed with an equivalent amount of water
(rendered acidic by hydrochloric acid) in the same manner as in
Example 25 or 26.
TABLE IV
__________________________________________________________________________
Solid Total Content Luminous Base in Coating Trans- Durability
Material*.sup.1 Protecting Coating Material Solution (%) mittance
(%) Test*.sup.2
__________________________________________________________________________
A Not coated -- 98.2 Poor A .gamma.-Glycidoxypropyltrimethoxy 2
97.0 Good silane/methanol silica sol (50/50) A
Methyltrimethoxysilane 1 97.1 Good A Methyltrimethoxysilane/ 3 96.3
Good methanol silica sol (50/50) A .gamma.-Glycidoxypropylmethyl- 1
96.9 Good diethoxysilane A .gamma.-Glycidoxypropylmethyl- 2 97.0
Good diethoxysilane/methanol silica sol (50/50) A
.gamma.-Glycidoxypropylmethyl- 1 96.2 Good diethoxysilane/phenyl-
trimethoxysilane (50/50) A .gamma.-Glycidoxypropylmethyl- 1 97.0
Good diethoxysilane/ .gamma.-chloropropyltrimethoxy- silane (50/50)
A .gamma.-Glycidoxypropylmethyl 1 96.5 Good
diethoxysilane/.beta.-(3,4- epoxycyclohexyl)ethyl- trimethoxysilane
(50/50) B .gamma.-Glycidoxypropylmethyl- 0.5 97.1 Good
diethoxysilane B Methyltrimethoxysilane 0.5 96.8 Good B
.gamma.-Glycidoxypropyltrime- 0.5 96.1 Good thoxysilane/Epikote
827*.sup.3 (20/10) B .gamma.-Glycidoxypropyltrime- 0.5 95.7 Good
thoxysilane/Denacol EX314*.sup.4 (20/20) B
.gamma.-Glycidoxypropyltrime- 0.5 96.3 Good thoxysilane/Denacol
EX820*.sup.5 (20/10) B .gamma.-Glycidoxypropyltrime- 0.5 96.1 Good
thoxysilane/Shodyne 508*.sup.6
__________________________________________________________________________
Note *.sup.1 A: plastic lens having an antireflective layer, formed
in Example 25 B: plastic lens having an antireflective layer,
formed in Example 26 *.sup.2 Adhesion test after hot water dipping
at 70.degree. C. for 30 minutes, and friction test with wool felt
under a load of 130 g, repeated 200 times *.sup.3 Bisphenol type
epoxy resin (manufactured by Shell Kagaku Kabushik Kaisha) *.sup.4
Glycerol polyglycidyl ether (manufactured by Nagase Sangyo
Kabushiki Kaisha) *.sup.5 Polyethylene glycol diglycidyl ether
(manufactured by Nagase Sangyo Kabushiki Kaisha) *.sup.6 Diglycidyl
phthalate (manufactured by Showa Denko Kabushiki Kaisha)
EXAMPLE 28
In coating a lens having an anti-reflective layer, obtained
according to the method described in Example 26, with a protecting
coating material, the amount coated was varied by increasing or
decreasing the amount of the solvent in the coating solution. The
obtained results are shown in Table V, below, from which it will
readily be understood that the anti-reflective effect is degraded
if the amount coated is too large.
TABLE V ______________________________________ Total Luminous
Amount of Protecting Coating Transmittance Material (mg/m.sup.2)
(%) ______________________________________ 0 98.3 20 97.2 50 96.2
100 95.6 1,200 92.3 ______________________________________
EXAMPLE 29
(1) Preparation of Acrylic Resin
A mixture of monomers, catalyst and chain transfer agent, having a
composition shown below, was dropped into 100 g of n-propanol
maintained at 95.degree. C. over a period of 1 hour. The catalyst
to be added afterwards (azobisisobutyronitrile) was added two times
(at an interval of 30 minutes; the amount added at each time being
0.2 g), and then, polymerization was conducted for 1 hour.
______________________________________ Ethyl acrylate 66 g Methyl
methacrylate 10 g 2-Hydroxyethyl methacrylate 14 g Methacrylic acid
10 g n-Dodecylmercaptan 1 g Azobisisobutyronitrile 1 g
______________________________________
(2) Preparation of Glass-Coating Solution
A mixture of 48 g of the acrylic resin solution formed in (1)
above, 6 g of a melamine resin ("Cymel 303" manufactured by
American Cyanamid Co.) and 86.4 g of n-propanol was stirred and 100
g of propanol silica sol (having a solid content of 30% and an
average particle size of 13.+-.1 m.mu.) was added to the mixture
being stirred to form a coating solution.
(3) Coating of Glass and Activated Gas Treatment
A soda glass sheet was sufficiently washed and treated with a
silicone type coupling agent having a concentration of 2%. Then,
the glass sheet was dipped in the coating solution formed in (2)
above and coated with the coating solution, and the coated glass
sheet was cured at 180.degree. C. for 30 minutes to obtain a glass
sheet having a transparent coating. The total luminous
transmittance of the glass sheet was 91.6%.
The coated glass sheet was subjected to the activated gas treatment
using oxygen for 4 minutes in the same manner as described in
Example 26. The total luminous transmittance of the so treated
coated glass sheet was 97.8%, and the glass sheet was found to have
an anti-reflective effect.
(4) Coating with Protecting Coating Material
The coating material formed in (2) above was diluted with
n-propanol so that the solid content was 1% by weight, and the
anti-reflective glass sheet formed in (3) above was dip-coated with
the so prepared protecting coating material, at a pull-out speed of
10 cm/min. The coated glass sheet was cured at 180.degree. C. for
20 minutes. The total luminous transmittance of the obtained coated
glass sheet was 96.2%, and even when the abrasive test using wool
felt was carried out 500 times, no peeling of the anti-reflective
coating was observed. When the comparative glass sheet having no
protecting coating was subjected to abrasive test in the same
manner as above, peeling of the anti-reflective layer was
observed.
EXAMPLE 30
A lens sample having an anti-reflective layer was prepared by
conducting the treatments up to the activated gas treatment in the
same manner as described in Example 26. This lens sample was coated
with a coating material (A) described in (a) below at a pull-out
speed of 10 cm/min and was then heated and dried at 82.degree. C.
for 10 minutes. Then, the coated lens was further coated with a
coating material (B) described in (b) below at a pull-out speed of
10 cm/min. The coated lens was preliminarily dried at 82.degree. C.
for 10 minutes and then cured at 130.degree. C. for 2 hours. The
obtained lens sample had a total luminous transmittance of 96.7%
and exhibited very light blue reflection interference color. The
lens was scratched only to a negligible extent by rubbing it with
steel wool (#0000), and even if it was dipped in hot water at
80.degree. C. for 1 hour, no change was observed. Furthermore, when
it was subjected to the outdoor exposure test for two months in
Florida, USA, no change was observed. This lens could be dyed with
a disperse dye stuff.
(a) The protecting coating material (A) was prepared in the
following manner.
A liquid mixture of 11.1 g of
.gamma.-(N-2-aminoethyl)aminopropyltrimethoxysilane ("SH-6020"
manufactured and sold by Toray Silicone Kabushiki Kaisha) and 24.2
g of methanol was hydrolyzed with 2.7 g of 0.01 N hydrochloric acid
at 20.degree. C. Then, 500 g of methanol was added to 0.5 g of the
obtained liquid product to adjust the solid content to 0.02% by
weight.
(b) The protecting coating material (B) was prepared in the
following manner.
A solution of hydrolyzed .gamma.-glycidoxypropyltrimethoxysilane in
n-propyl alcohol was prepared in the same manner as described in
Example 26. The solid content of the solution was 0.5% by
weight.
* * * * *